Abnormal proteins cause rosacea

Results of study could aid researchers in finding cure for skin ailment

Results of study could aid researchers in finding cure for skin ailment

August 06, 2007|By Alison Williams, Los Angeles Times

Researchers have solved a medical mystery that has eluded them for hundreds of years, demonstrating that an abundance of abnormal skin proteins causes the blotchy skin condition called rosacea. In a study published Sunday in the online edition of the journal Nature Medicine, scientists showed that people with rosacea have too much of a protein called cathelicidin that is processed incorrectly. The results could aid researchers in designing an effective treatment for the disease, which affects 14 million people in the United States. “We haven't had this kind of important finding in the study of rosacea for a long time,” said dermatologist Jenny Kim of David Geffen School of Medicine at the University of California, Los Angeles, who was not involved in the study. Rosacea is a skin disease that causes redness, visible blood vessels, bumps and pimples on the face. It tends to strike more women, usually between ages 30 and 60, but men often have more severe symptoms. “It's an appearance-related disease, so many people suffer from low self-esteem, and that can affect their everyday life,” Kim said. Options for treatment include light therapy to decrease redness, avoiding known triggers such as spicy foods and heat, and prescribing antibiotics that don't work for every patient. “Treatment could now be much more rationally designed,” said Dr. Robert Gallo, chairman of dermatology at the University of California, San Diego, and senior author of the study. About a dozen years ago, researchers in Gallo's lab discovered cathelicidin proteins, which help defend against infections in the skin. Gallo and his colleagues went on to find an association between the protein and skin conditions such as eczema. The team later found that cathelicidin could cause the redness that is the hallmark of rosacea, so they started searching for a link. The researchers took skin biopsies from 11 people with rosacea and 10 healthy people who served as controls. What they found was “a double hit of things going abnormally,” Gallo said. All the rosacea patients had too much cathelicidin, most of which was abnormal. There also was an abundance of a molecule that processes cathelicidin from an inactive to an active form. Experiments on mice confirmed the theory. One of the most common treatments for rosacea is the antibiotic tetracycline. The study suggests that the drug is successful in rosacea patients because it inhibits cathelicidin processing, not because of its bacterial-killing properties. Future treatments might target the excessive production of cathelicidin's precursor, Gallo said.